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#10511: clarification of what heaps are; suggested by Johannes Hoff.

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Georg Brandl 2010-11-23 08:37:54 +00:00
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Doc/library/heapq.rst
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@ -16,11 +16,12 @@ as the priority queue algorithm.
Latest version of the :source:`heapq Python source code
<Lib/heapq.py>`
Heaps are arrays for which ``heap[k] <= heap[2*k+1]`` and ``heap[k] <=
heap[2*k+2]`` for all *k*, counting elements from zero. For the sake of
comparison, non-existing elements are considered to be infinite. The
interesting property of a heap is that ``heap[0]`` is always its smallest
element.
Heaps are binary trees for which every parent node has a value less than or
equal to any of its children. This implementation uses arrays for which
``heap[k] <= heap[2*k+1]`` and ``heap[k] <= heap[2*k+2]`` for all *k*, counting
elements from zero. For the sake of comparison, non-existing elements are
considered to be infinite. The interesting property of a heap is that its
smallest element is always the root, ``heap[0]``.
The API below differs from textbook heap algorithms in two aspects: (a) We use
zero-based indexing. This makes the relationship between the index for a node